Pregnancy nausea: a discovery could soon put an end to it

Eight out of ten women experience nausea at some point during their pregnancy. Among them, 2% suffer from hyperemesis gravidarum, vomiting such that it sometimes requires hospitalization to protect the mother and child. However, although pregnancy nausea affects a majority of women, its causes have not yet been well established… and therefore not well managed. But a study carried out by researchers at the University of Cambridge has found the culprit.

A hormone produced by the placenta in question

Recently, some evidence from genetic studies has suggested that pregnancy nausea may be linked to the placenta’s production of the hormone GDF15, which acts on the mother’s brain. Now an international study, involving scientists from the University of Cambridge and researchers from Scotland, the United States and Sri Lanka, has made major progress in understanding the role of this hormone in disease. linked to pregnancy, in particular hyperemesis gravidarum.

The team analyzed data from female participants in a number of studies. They used a combination of approaches including human genetics, new methods of analyzing hormones in the blood of pregnant women, and studies in cells and mice.

Result: the researchers showed that the intensity of nausea and vomiting experienced was directly linked both to the quantity of GDF15 produced by the fetal part of the placenta and sent into its blood, and to its sensitivity to the effect of this hormone.

Thus, GDF15 is produced in low quantities in all tissues outside of pregnancy. When produced during pregnancy, women with normally low blood GDF15 levels have a higher risk of developing severe nausea and vomiting during pregnancy. Conversely, women with the hereditary blood disorder beta thalassemia, which causes them to have naturally very high levels of GDF15 before pregnancy, experience little or no nausea or vomiting.

Control the production of hormones to control nausea?

For Professor Sir Stephen O’Rahilly, from the Wellcome-Medical Research Council Institute of Metabolic Sciences at the University of Cambridge, who led the research, this discovery is a first step towards improving the well-being of pregnant women:

“We now know why women feel this nausea: the growing baby in the womb produces a hormone at levels the mother is not used to. The more sensitive she is to this hormone, the sicker she will become. This knowledge gives us an idea of ​​how we might prevent this from happening.”

In fact, an effective way to treat this disorder would ultimately be to block GDF15 from accessing its highly specific receptor in the mother’s brain. Or to strengthen your tolerance before pregnancy. To this end, the researchers demonstrated that mice treated with a long-acting form of GDF15 did not experience nausea when exposed to acute levels of the hormone.

The next step would therefore be to test whether administering GDF15 to women with a history of hyperemesis gravidarum before pregnancy can reduce nausea and vomiting, or even prevent symptoms.